One example of a developing cartridge mountable in an electrophotographic image forming apparatus has a developing roller for carrying toner. This developing cartridge is first mounted in a drum cartridge possessing a photosensitive drum, before being mounted in the image forming apparatus.
Japanese Patent Application Publication No. 2011-39561 has proposed a developing cartridge which is provided with a drive-force receiving developing gear. The drive-force receiving developing gear receives an inputted drive force for driving the developing roller and the like.